1. Field of the Invention
The present invention relates to generating and executing voice enabled web applications within a hypertext markup language (HTML) and hypertext transport protocol (HTTP) framework.
2. Description of the Related Art
The evolution of the public switched telephone network has resulted in a variety of voice applications and services that can be provided to individual subscribers and business subscribers. Such services include voice messaging systems that enable landline or wireless subscribers to record, playback, and forward voice mail messages. However, the ability to provide enhanced services to subscribers of the public switched telephone network is directly affected by the limitations of the public switched telephone network. In particular, the public switched telephone network operates according to a protocol that is specifically designed for the transport of voice signals; hence any modifications necessary to provide enhanced services can only be done by switch vendors that have sufficient know-how of the existing public switched telephone network infrastructure.
An open standards-based Internet protocol (IP) network, such as the World Wide Web, the Internet, or a corporate intranet, provides client-server type application services for clients by enabling the clients to request application services from remote servers using standardized protocols, for example hypertext transport protocol (HTTP). The web server application environment can include web server software, such as Apache-based software available from The Apache Software Foundation, implemented on a computer system attached to the IP network. Web-based applications are composed of HTML pages, logic, and database functions. In addition, the web server may provide logging and monitoring capabilities.
In contrast to the public switched telephone network, the open standards-based IP network has enabled the proliferation of web based applications written by web application developers using ever increasing web development tools. Hence, the ever increasing popularity of web applications and web development tools provides substantial resources for application developers to develop robust web applications in a relatively short time and an economical manner. However, one important distinction between telephony-based applications and web-based applications is that telephony-based applications are state aware, whereas web-based applications are stateless.
In particular, telephony applications are state aware to ensure that prescribed operations between the telephony application servers and the user telephony devices occur in a prescribed sequence. For example, operations such as call processing operations, voicemail operations, call forwarding, etc., require that specific actions occur in a specific sequence to enable the multiple components of the public switched telephone network to complete the prescribed operations.
The web-based applications running in the IP network, however, are state-less and transient in nature, and do not maintain application state because application state requires an interactive communication between the browser and back-end database servers accessed by the browsers via a HTTP-based web server. However, an HTTP server provides asynchronous execution of HTML applications, where the web applications in response to reception of a specific request in the form of a URL from a client, instantiate a program configured for execution of the specific request, send an HTML web page back to the client, and terminate the program instance that executed the specific request. Storage of application state information in the form of a “cookie” is not practical because some users prefer not to enable cookies on their browser, and because the passing of a large amount of state information as would normally be required for voice-type applications between the browser and the web application would substantially reduce the bandwidth available for the client.
Commonly-assigned, copending application Ser. No. 09/480,485, filed Jan. 11, 2000, entitled Application Server Configured for Dynamically Generating Web Pages for Voice Enabled Web Applications, the disclosure of which is incorporated in its entirety herein by reference, discloses an application server that executes a voice-enabled web application by runtime execution of extensible markup language (XML) documents that define the voice-enabled web application to be executed. The application server includes a runtime environment that establishes an efficient, high-speed connection to a web server. The application server, in response to receiving a user request from a user, accesses a selected XML page that defines at least a part of the voice application to be executed for the user. The XML page may describe any one of a user interface such as dynamic generation of a menu of options or a prompt for a password, an application logic operation, or a function capability such as generating a function call to an external resource. The application server then parses the XML page, and executes the operation described by the XML page, for example dynamically generating an HTML page having voice application control content, or fetching another XML page to continue application processing. In addition, the application server may access an XML page that stores application state information, enabling the application server to be state-aware relative to the user interaction. Hence, the XML page, which can be written using a conventional editor or word processor, defines the application to be executed by the application server within the runtime environment, enabling voice enabled web applications to be generated and executed without the necessity of programming language environments.
Hence, web programmers can write voice-enabled web applications, using the teachings of the above-incorporated application Ser. No. 09/480,485, by writing XML pages that specify respective voice application operations to be performed. The XML documents have a distinct feature of having tags that allow a web browser (or other software) to identify information as being a specific kind or type of information. In particular, commonly-assigned, copending application Ser. No. 09/501,516, filed Feb. 1, 2000 entitled Arrangement for Defining and Processing Voice Enabled Web Applications Using Extensible Markup Language Documents, the disclosure of which is incorporated in its entirety herein by reference, discloses an arrangement for defining a voice-enabled web application using extensible markup language (XML) documents that define the voice application operations to be performed within the voice application. Each voice application operation can be defined as any one of a user interface operation, a logic operation, or a function operation. Each XML document includes XML tags that specify the user interface operation, the logic operation and/or the function operation to be performed within a corresponding voice application operation, the XML tags being based on prescribed rule sets that specify the executable functions to be performed by the application runtime environment. Each XML document may also reference another XML document to be executed based on the relative position of the XML document within the sequence of voice application operations to be performed. The XML documents are stored for execution of the voice application by an application server in an application runtime environment.
Hence, the XML document described in the above-incorporated application Ser. No. 09/501,516, which can be written using a conventional editor or word processor, defines the application to be executed by the application server within the runtime environment, enabling voice enabled web applications to be generated and executed without the necessity of programming language environments.
Conventional application development environments maintain a substantial distinction between application use and application development. In particular, most applications are developed either by writing source code using a conventional programming language and compiling the written code into executable format, or using a stand-alone development tool that generates the required application. After the application has been developed into executable code, the executable code is then executed by a processing system for testing prior to actual use by subscribers. The distinction between application use and application development hinders efficiency in application development, since a developer is unable to obtain immediate feedback from adding any changes to an application. Hence, an application developer having discovered an undesirable result in the application during execution typically needs to retrace the executable code to locate the cause of the undesirable result, slowing the application development process.